Lower extremity stiffness: considerations for testing, performance enhancement, and injury risk
AffiliationCity and Islington College
University of Bedfordshire
Aspetar Orthopaedic and Sports Medicine Hospital, Doha
C600 Sports Science
MetadataShow full item record
AbstractBrazier, J, Maloney, S, Bishop, C, Read, PJ, and Turner, AN. Lower extremity stiffness: considerations for testing, performance enhancement, and injury risk. J Strength Cond Res 33(4): 1156-1166, 2019 - Force-deformation characteristics of the lower limb have been associated with athletic performance and may modulate the risk of injury. Despite these known associations, measurements of lower extremity stiffness are not commonly administered by strength and conditioning coaches. This review provides an overview of the available literature pertaining to the effects of lower extremity stiffness on physical performance and injury risk. Practical methods of monitoring and training stiffness are also discussed. The cumulative body of evidence indicates that increases in lower extremity stiffness are associated with heightened performance in athletic tasks such as hopping, jumping, throwing, endurance running, sprinting, and changing direction. Relationships with injury are less conclusive because both excessive and insufficient limb stiffness have been postulated to increase risk. Thus, the optimal level of stiffness seems to be dependent on the anthropometry and physical capabilities of the athlete, in addition to sport-specific activity demands. Training interventions can positively enhance lower extremity stiffness, including isometric, eccentric, and isotonic strength training and plyometrics. Complex training also seems to provide a potent stimulus and may be more effective than the use of singular training modes. For plyometric activities, it is recommended that coaches use a developmental sequence of exercises with increasing eccentric demand to provide an appropriate stimulus based on the training age and technical competency of the athlete.
CitationBrazier J, Maloney S, Bishop C, Read P, Turner A (2019) 'Lower extremity stiffness: considerations for testing, performance enhancement, and injury risk', Journal of Strength and Conditioning Research, 33 (4), pp.1156-1166.
- Neuro-musculoskeletal and performance adaptations to lower-extremity plyometric training.
- Authors: Markovic G, Mikulic P
- Issue date: 2010 Oct 1
- Differences in lower extremity stiffness between endurance-trained athletes and untrained subjects.
- Authors: Hobara H, Kimura K, Omuro K, Gomi K, Muraoka T, Sakamoto M, Kanosue K
- Issue date: 2010 Jan
- Reactive and eccentric strength contribute to stiffness regulation during maximum velocity sprinting in team sport athletes and highly trained sprinters.
- Authors: Douglas J, Pearson S, Ross A, McGuigan M
- Issue date: 2020 Jan
- The relationship between mechanical stiffness and athletic performance markers in sub-elite footballers.
- Authors: Kalkhoven JT, Watsford ML
- Issue date: 2018 May
- The combination of plyometric and balance training improves sprint and shuttle run performances more often than plyometric-only training with children.
- Authors: Chaouachi A, Othman AB, Hammami R, Drinkwater EJ, Behm DG
- Issue date: 2014 Feb
Showing items related by title, author, creator and subject.
Unilateral stiffness interventions augment vertical stiffness and change of direction speedMaloney, Sean J.; Richards, Joanna C.; Jelly, Luke; Fletcher, Iain M. (Lippincott, Williams & Wilkins, 2017-07-13)It has previously been shown that pre-conditioning interventions can augment change of direction speed (CODS). However, the mechanistic nature of these augmentations has not been well considered. The current study sought to determine the effects of pre-conditioning interventions designed to augment vertical stiffness on CODS. Following familiarization, ten healthy males (age: 22 ± 2 years; height: 1.78 ± 0.05 m; body mass: 75.1 ± 8.7 kg) performed three different stiffness interventions in a randomized and counterbalanced order. The interventions were: a) bilateral-focused, b) unilateral-focused, and c) a control of CODS test practice. Vertical stiffness and joint stiffness was determined pre- and post-intervention using a single leg drop jump task. CODS test performance was assessed post-intervention using a double 90o cutting task. Performances following the unilateral intervention were significantly faster than control (1.7%; P = 0.011; d = -1.08), but not significantly faster than the bilateral intervention (1.0% faster; P = 0.14; d = -0.59). Versus control, vertical stiffness was 14% greater (P = 0.049; d = 0.39) following the unilateral intervention and 11% greater (P = 0.019; d = 0.31) following the bilateral intervention; there was no difference between unilateral and bilateral interventions (P = 0.94; d = -0.08). The findings of the current study suggest that unilateral pre-conditioning interventions designed to augment vertical stiffness improve CODS within this experimental cohort.
Vertical stiffness asymmetries during drop jumping are related to ankle stiffness asymmetriesMaloney, Sean J.; Richards, Joanna C.; Nixon, Daniel G.D.; Harvey, Lewis J.; Fletcher, Iain M. (Wiley, 2016-03-31)Asymmetry in vertical stiffness has been associated with increased injury incidence and impaired performance. The determinants of vertical stiffness asymmetry have not been previously investigated. Eighteen healthy males performed three unilateral drop jumps during which vertical stiffness and joint stiffness of the ankle and knee were calculated. Reactive strength index was also determined during the jumps using the ratio of flight time to ground contact time. ‘Moderate’ differences in vertical stiffness (t17 = 5.49; P < 0.001), ‘small’ differences in centre of mass displacement (t17 = -2.19; P = 0.043) and ‘trivial’ differences in ankle stiffness (t17 = 2.68; P = 0.016) were observed between stiff and compliant limbs. A model including ankle stiffness and reactive strength index symmetry angles explained 79% of the variance in vertical stiffness asymmetry (R2 = 0.79; P < 0.001). None of the symmetry angles were correlated to jump height or reactive strength index. Results suggest that asymmetries in ankle stiffness may play an important role in modulating vertical stiffness asymmetry in recreationally trained males.
Reliability of unilateral vertical leg stiffness measures assessed during bilateral hoppingMaloney, Sean J.; Fletcher, Iain M.; Richards, Joanna C.; University of Bedfordshire (Human Kinetics, 2019-03-15)The assessment of vertical leg stiffness is an important consideration given its relationship to performance. Vertical stiffness is most commonly assessed during a bilateral hopping task. The current study sought to determine the inter-session reliability, quantified by the coefficient of variation, of vertical stiffness during bilateral hopping when assessed for the left and right limbs independently, this had not been previously investigated. On four separate occasions, ten healthy males performed 30 unshod bilateral hops on a dual force plate system with data recorded independently for the left and right limbs. Vertical stiffness was calculated as the ratio of peak ground reaction force to the peak negative displacement of the centre of mass during each hop and was averaged over the 6-10th hops. For vertical stiffness, average coefficients of variation of 15.3% and 14.3% were observed for the left and right limbs respectively. An average coefficient of variation of 14.7% was observed for bilateral vertical stiffness. The current study reports that calculations of unilateral vertical stiffness demonstrate reliability comparable to bilateral calculations. Determining unilateral vertical stiffness values and relative discrepancies may allow the coach to build a more complete stiffness profile of an individual athlete and better inform the training process.